We hypothesize that because of cocaine's effect on the developing catecholamine system, prenatal cocaine exposure (CE) should interfere with the infant's ability to regulate and control arousal. This effect produces a style of responding to the environment that is characterized by seeking stimulation more than usual and is hypothesized to affect normal development of attention and subsequent behavior. Thus, CE infants will differ in how they integrate arousal and attention as compared to (a) non- CE infants, and (b) infants with other CNS risk conditions. Furthermore, we hypothesize that these differences should persist through the first 19 months of age and be detected primarily using tasks that require control of stimulation. Strong evidence now indicates that CE infants tend to look at more stimulating events regardless of manipulations of arousal that would normally shift attention to less stimulating events. Current aims are designed to manipulate a vanity of situations for which hypothesized responses with respect to stimulation can be evaluated. First, we predict that CE infants during the newborn period, in contrast to both normal infants and infants with documented CNS pathology, will display this stimulus-seeking behavior in a number of different converging tasks in which arousal is manipulated by feeding or amount of stimulation. Second, we propose to extend the study of the interaction of early CE with developmental changes in attention and perception to determine whether development of short-term memory and of response to stimulus change, complex patterns, and auditory-visual synchrony are altered. We predict that CE, acting through the substrate of early arousal/attention organization, will interfere with the normal development of these processes when evaluated at specific intervals during the first year. Third, we propose to determine if there is a relationship of early cocaine exposure with (a) perceptual and motivational development between 10 and 19 months, as measured by focused attention, distractibility, and exploratory behavior and (b) general cognitive growth particularly as altered by CNS status. Finally we wish to determine if the different developmental trajectory of mental function observed in CE infants reflects CNS injury, differential environmental experience, or intrauterine CE by studying infants of cocaine using mothers seeking rehabilitation program. A 5-year project initially studying 384 infants, with 192 completing all aspects of the study is proposed.